How do I calculate trailer payload capacity?

Subtract the trailer's empty weight from its GVWR, both of which are on the VIN plate. A 7,000-pound GVWR trailer weighing 1,900 empty carries 5,100 pounds of cargo. That is the trailer's own limit, set by its axles, tyres and frame, and it is separate from what your vehicle can pull.

What is the correct tongue weight for a trailer?

Ten to fifteen percent of the loaded trailer weight for a conventional bumper-pull trailer. Too little is the dangerous direction — a light tongue lets the trailer sway, and sway is self-amplifying at highway speed. Too much overloads the hitch and lifts weight off the tow vehicle's front axle, which costs you steering.

Why does my trailer sway at highway speed?

Almost always insufficient tongue weight, meaning too much load behind the axle. Sway is a feedback loop — a small yaw pushes the tow vehicle, which pushes back harder, and the oscillation grows. The fix is to move load forward of the axle rather than to drive more carefully. A sway control bar treats the symptom, not the cause.

Can I tow at exactly my vehicle's rated capacity?

You can, but tow ratings are established under specific conditions — often a lightly loaded vehicle with a driver and nothing else. Passengers, cargo and the tongue weight itself all consume the vehicle's payload, and running at the ceiling leaves nothing for grades, heat or a hard stop. Eighty percent is a much more comfortable place to be.

Which limit actually binds?

Whichever comes first, and it varies. Small utility trailers usually hit their own payload capacity first; large ones hit the tow vehicle's capacity; and a lot of half-ton pickups hit the hitch or the vehicle's payload long before the advertised tow rating. All of them have to be satisfied, not just the one you remember.

Trailer Load and Tongue Weight Calculator

Check a trailer load against four separate limits — trailer payload, GVWR, tow capacity and hitch rating — and whether tongue weight sits in the stable range.

By StatesideCalc EditorialLast verified July 27, 2026

Trailer GVWR

From the trailer's VIN plate. Maximum loaded weight it is rated for.

Trailer empty weight

Tow vehicle capacity

From the owner's manual for your exact configuration, not the marketing figure.

Hitch weight rating

Cargo weight

Everything on the trailer, including fuel, water and anything strapped to it.

Tongue weight

Share of loaded weight on the hitch. 10–15% is the stable range.

Within every limit, at 95.1% of the binding one. Tongue weight of 732 lb sits inside the 10–15% band, which is what keeps the trailer tracking straight.

What this calculator does

Trailer GVWR and empty weight, your tow vehicle’s capacity and hitch rating, your cargo weight and your tongue weight percentage go in. It checks all four limits, reports which are satisfied, shows the tongue weight against the recommended band, and tells you what percentage of the binding limit you are using.

Four separate limits, because towing is a problem where satisfying three of them is the same as satisfying none.

The four limits

Trailer payload capacity — GVWR minus the trailer’s empty weight. This is the trailer’s own limit, set by its axles, tyres, springs and frame. Both numbers are on the VIN plate riveted to the tongue or frame rail.

Loaded trailer weight against the tow vehicle’s capacity — what your vehicle is rated to pull. From the owner’s manual, for your exact engine, axle ratio, cab configuration and drivetrain. Not the number in the advertisement, which describes the one configuration that achieved it.

Tongue weight against the hitch rating — every hitch and every receiver has its own limit, and they are frequently lower than people expect. A hitch rated for 5,000 pounds towing is often rated for only 500 pounds of tongue weight.

Tongue weight as a percentage of loaded weight — not a rating at all, but a stability requirement. Covered below, and it is the one that actually causes crashes.

Every one of these has to be satisfied. Which one binds varies: small utility trailers usually run out of their own payload first, large ones hit the tow vehicle, and a lot of half-ton pickups hit the hitch or the vehicle’s payload capacity long before the advertised tow rating.

Tongue weight, and why sway happens

This is the section worth reading properly, because it is where towing goes wrong in a way that is genuinely dangerous.

Tongue weight is the downward force the trailer coupler puts on the hitch ball. It should be 10 to 15 percent of the loaded trailer weight for a conventional bumper-pull trailer.

Too little tongue weight — meaning too much load behind the trailer axle — produces sway. And sway is not a nuisance. It is a self-amplifying oscillation: a small yaw of the trailer pushes the back of the tow vehicle sideways, which steers the vehicle slightly, which pushes the trailer harder in the opposite direction, which pushes back harder still.

The amplitude grows with each cycle, and the whole feedback loop becomes more energetic with speed. Above a threshold it diverges, and a driver who reacts by steering makes it worse. The recovery technique is to ease off the throttle and apply the trailer brakes if you have them — counter-intuitive, and worth knowing before you need it.

Too much tongue weight is safer but not fine. It overloads the hitch, compresses the tow vehicle’s rear suspension, and lifts weight off the front axle — which is where your steering and most of your braking are. A vehicle squatting badly at the rear has light, vague steering exactly when it most needs grip.

How to load a trailer

The rule that produces correct tongue weight without measuring anything:

Roughly 60 percent of the load ahead of the axle, 40 percent behind.

Then:

Heaviest items first, low, and over or just ahead of the axle. A low centre of gravity resists both sway and rollover.
Distribute side to side. Uneven lateral loading overloads one tyre and makes the trailer track crooked.
Strap everything. Load that shifts at speed changes your tongue weight mid-corner, which is the worst possible moment.
Check tyre pressure, on the trailer and the tow vehicle. Trailer tyres run at high pressures and fail dramatically when underinflated — and they age out on time rather than tread depth.

To measure tongue weight rather than estimate it: a bathroom scale under the jack works for light trailers; a dedicated tongue weight scale for heavier ones; or weigh the whole rig at a truck scale with and without the tongue on the ball.

Weights that surprise people

Cargo weight is the input most often guessed and most often wrong. Some anchors:

Lumber: about 3 lb per board foot kiln-dried softwood. The board foot calculator converts a lumber list into a weight, and the answers are frequently over a ton.
Aggregate: crushed stone is roughly 2,800 lb per cubic yard. One yard of gravel is 1.4 tons. See the cubic yards to tons converter.
Concrete: about 4,000 lb per cubic yard.
Water: 8.34 lb per gallon. A 100-gallon tank is 834 lb before the tank.
Firewood: a cord of seasoned hardwood runs 2,500 to 4,000 lb.
A compact car: 2,700 to 3,500 lb.

Note that a single cubic yard of gravel — a small-looking pile — is close to the payload limit of many light utility trailers.

The limit this calculator does not check

The tow vehicle’s own payload capacity, on the door jamb sticker.

Tongue weight sits on the tow vehicle and consumes its payload. So do passengers, so does anything in the bed or the boot, and so does a weight distribution hitch. A half-ton pickup advertised at a large tow rating frequently runs out of payload with a family aboard and 800 pounds on the ball, well before the tow rating is anywhere near reached.

Also unchecked here: the gross combined weight rating for vehicle and trailer together, which is a separate ceiling over everything.

Both are on the vehicle. Read the sticker.

What this leaves out

Tow vehicle payload and gross combined rating, as above.
Weight distribution hitches, which redistribute tongue weight back onto the front axle and change the arithmetic substantially.
Trailer brake requirements, which kick in by weight and vary by state.
Licence class requirements for heavy combinations.
Fifth wheel and gooseneck towing, which uses a much higher pin weight percentage — typically 15 to 25 percent — and different rules entirely.
Grade, altitude and heat, all of which reduce real-world capability below the rating.

How this is calculated

trailer payload capacity = trailer GVWR − trailer empty weight loaded trailer weight = empty weight + cargo tongue weight = loaded weight × tongue percentage target band = 10% to 15% of loaded weight

Frequently asked questions

How do I calculate trailer payload capacity?: Subtract the trailer's empty weight from its GVWR, both of which are on the VIN plate. A 7,000-pound GVWR trailer weighing 1,900 empty carries 5,100 pounds of cargo. That is the trailer's own limit, set by its axles, tyres and frame, and it is separate from what your vehicle can pull.
What is the correct tongue weight for a trailer?: Ten to fifteen percent of the loaded trailer weight for a conventional bumper-pull trailer. Too little is the dangerous direction — a light tongue lets the trailer sway, and sway is self-amplifying at highway speed. Too much overloads the hitch and lifts weight off the tow vehicle's front axle, which costs you steering.
Why does my trailer sway at highway speed?: Almost always insufficient tongue weight, meaning too much load behind the axle. Sway is a feedback loop — a small yaw pushes the tow vehicle, which pushes back harder, and the oscillation grows. The fix is to move load forward of the axle rather than to drive more carefully. A sway control bar treats the symptom, not the cause.
Can I tow at exactly my vehicle's rated capacity?: You can, but tow ratings are established under specific conditions — often a lightly loaded vehicle with a driver and nothing else. Passengers, cargo and the tongue weight itself all consume the vehicle's payload, and running at the ceiling leaves nothing for grades, heat or a hard stop. Eighty percent is a much more comfortable place to be.
Which limit actually binds?: Whichever comes first, and it varies. Small utility trailers usually hit their own payload capacity first; large ones hit the tow vehicle's capacity; and a lot of half-ton pickups hit the hitch or the vehicle's payload long before the advertised tow rating. All of them have to be satisfied, not just the one you remember.